1. Field of the Invention
The present invention relates to a hot water-water mixing faucet and ejecting the mixture. Particularly, the present invention relates to the improvement of a valve for mixing cold and hot water having an embodiment in which a hot-water inlet and a cold-water inlet are provided parallel in an axial direction on a peripheral wall of a cylindrical casing which is formed cylindrically and incorporated in the form of a cartridge into a cylindrically formed casing which is an external housing of the hot water-water mixing faucet. A hot-water valve seat and a cold-water valve seat are provided in the axial direction in inner surfaces of the hot-water inlet and the cold-water inlet respectively such that they face each other. A cylinder control valve body, which comprises, at both axial ends thereof, a hot-water valve and a cold-water valve which face the hot-water valve seat and the cold-water valve seat respectively, is disposed in the casing so as to be able to move in the axial direction. A leading end of a temperature-sensitive coil spring, which supports a rear end thereof using the casing, and a leading end of a bias spring, which supports a rear end thereof using an adjusting screw, are caused to face each other and coupled with each other in the control valve body, which is supported by the balance between the pair of springs so as to be able to move in the axial direction. When the hot water and the cold water, which flow in from the hot-water inlet and the cold-water inlet respectively, are mixed and the mixture is ejected, the temperature-sensitive coil spring is caused to sense the temperature of the mixture, and a change of the spring constant of the temperature-sensitive coil spring in accordance with the change of the temperature causes the control valve body to perform control operation, whereby the temperature of the ejected mixture is kept at a set temperature.
2. Discussion of the Related Art
The hot water-water mixing faucet is configured as shown in FIG. 1 and FIG. 2, such that the control valve provided so as to be able to move in the axial direction is held in a state in which the temperature-sensitive coil spring and the bias spring are balanced, and that the operation of the control valve is controlled automatically by the temperature-sensing operation of the temperature-sensitive coil spring so that the temperature of the ejected mixture is kept at the set temperature.
In FIG. 1, a dashed line 1 is a cylindrically formed external housing (case), which is an external box of a hot water-water mixing faucet A which is constructed and installed for the purpose of supplying hot water/cold water to a bathroom or the like, wherein a cylinder wall thereof is provided with a hot-water inlet pipe 10 connected to a hot-water faucet, a cold-water inlet pipe 11 connected to a cold-water faucet, and an ejection pipe 12 for ejecting a mixture.
2 is a casing, which is fitted into the external housing 1 and assembles a control valve mechanism w to be incorporated in the form of a cartridge. The casing is formed into a cylinder so as to be inserted into the external housing 1 by means of a closed-end cylindrical main body 2a and a valve seat clamp 2b screwed into the cylindrical main body 2a, and a hot-water inlet 20 and a cold-water inlet 21 are formed axially (longitudinal direction in FIG. 1) with a space therebetween on a peripheral wall of the casing. Furthermore, a hot-water valve seat a and a cold-water valve seat b are formed on an inner position of each of the hot-water inlet 20 and cold-water inlet 21 so as to face each other as a pair.
3 is a control valve body, which is disposed between the space formed by the hot-water valve seat a and the cold-water valve seat b facing each other, so as to be able to move axially in the space, the control valve body being formed into a cylindrical valve, wherein a hot-water valve 3a is provided on the side facing the hot-water valve seat a, and a cold-water valve 3b is formed on an edge on the side facing the cold-water valve seat b.
4 is a bias spring, which biases the control valve body 3 such as to push the control valve body 3 out toward the cold-water valve seat b, and 5 is a temperature-sensitive coil spring, which biases the control valve body 3 such as to push the control valve body 3 out toward the hot-water valve seat a.
As the temperature-sensitive coil spring 5, a shape memory alloy (“SMA” for short) is used. The load on the temperature-sensitive coil spring is changed by the temperature because the elastic force is reduced by cooling the temperature-sensitive coil spring and increased by heating the temperature-sensitive coil spring, and the temperature-sensitive coil spring is stretched by the temperature since it is formed into a spring. Therefore, the stretching force is used as the load to operate the control valve body and control the control operation thereof, thus the temperature-sensitive coil spring is used in a temperature actuator.
6a is an adjusting screw, which supports a rear end side of the bias spring 4 and is incorporated so as to engage an outer peripheral surface thereof with an internal surface of the casing 2 so that the adjusting screw is regulated in a peripheral direction and moves in the axial direction, wherein a female screw is formed on an inner peripheral surface.
6b is an adjusting screw axis, which is provided in the casing 2 so as to be turned by a temperature-regulating dial D1 provided on one end of the casing 2, wherein a male screw is provided on an outer peripheral surface so that the adjusting screw axis is screwed to the adjusting screw 6a by the mail screw.
In the hot water-water mixing faucet A with such an embodiment, the adjusting screw 6a is displaced toward the axial direction by a turning operation of the temperature-regulating dial D1, a supporting position on other end of the bias spring 4 is set to a desired position, in which state the control valve body 3 is held in a position balanced by the bias spring 4 and the temperature-sensitive coil spring 5, the temperature-sensitive coil spring 5 performs a sensing operation in accordance with the change in the temperature of the mixture, and displaces the control valve body 3 using a biasing force of the bias spring when a generated load is changed, and the temperature of the mixture to be ejected is held at a set temperature.
More specifically, in FIG. 2, the control valve body 3 is supported so as to be able to move axially by coupling, at both ends thereof, a leading end of the bias spring 4, which supports a rear end thereof using the adjusting screw 6a, with a leading end of the temperature-sensitive coil spring 5, which supports a rear end thereof using the casing 2, and causing these leading ends to face each other. The control valve body 3 is also held in a position where the bias spring 4 and the temperature-sensitive coil spring 5 are balanced. Hot water, which flows from the hot-water inlet 20 into the casing 2 via a space between the hot-water valve 3a and the hot-water valve seat a, and cold water, which flows from the cold-water inlet 21 into the casing 2 via a space between the clod-water valve 3b and the cold-water valve seat b, merge and are mixed in a mixing chamber 22 formed on other end of the casing 2 to obtain a mixture. When the mixture is ejected from a mixture outlet 23, the temperature-sensitive coil spring 5, which is disposed in the mixing chamber 22, senses the temperature of the mixture and thereby changes a generated load, whereby control is performed so as to displace the control valve body 3 by using the biasing force of the bias spring 4, and further control is performed so as to keep the temperature of the mixture at a set desired temperature.
Specifically, when the flow volume of the flowing cold water decreases and thereby the temperature of the mixture inside the mixing chamber 22 increases, the temperature-sensitive coil spring 5 sensing such occurrence is operated so as to increase the generated load, the bias spring 4 is screwed by the amount of the increased load, the control valve body 3 is moved toward the left, the space between the hot-water valve 3a and the hot-water valve seat a is narrowed, and the flow volume of the hot water is reduced, whereby the increased temperature of the mixture is reduced. Consequently, the control valve body 3 is stabilized at the position where the mixture ratio between the hot-water and cold water in the mixture and the temperature of the mixture are balanced.
Further, in the case in which the flow volume of the flowing cold water increases because of the increase of water pressure, and thereby the temperature of the mixture inside the mixing chamber 22 decreases, the temperature-sensitive coil spring 5 operates to sense such occurrence and thereby reduces the generated load, the bias spring 4 is stretched out by the reduced amount of load, the control valve body 3 is moved toward the right, and the space between the cold-water valve 3b and the cold-water valve seat b is narrowed to reduce the flow volume of the flowing cold water and thus the amount of the cold water, whereby the reduced temperature of the mixture is increased. Consequently, the control valve body 3 is stabilized at the position where the mixture ratio between the flowing hot water and cold water and the temperature of the mixture are balanced.
In the hot water-water mixing faucet A having such an embodiment in which the temperature-sensitive coil spring 5 constituted by the SMA spring is used, the temperature-sensitive coil spring 5 being operated as described above, when ejecting the cold water, the adjusting screw 6a of a supporting member g supporting the other end of the bias spring 4 is moved toward the left by operating and turning the temperature-regulating dial D1, the control valve body 3 is displaced toward the hot-water valve seat a side, the space between the hot-water valve 3a and the hot-water valve seat a is completely closed, and the space between the cold-water valve seat b and the cold-water valve 3b is opened widely. At this moment, however, the temperature-sensitive coil spring 5 constituted by the SMA spring does not have sufficient power to press the control valve body 3 toward the hot-water valve seat a because the generated load is reduced by the reduction of the temperature, thus it is inevitable that the space between the hot-water valve seat a and the hot-water valve 3a cannot be closed completely.
In order to cope with such a circumstance, it is required that the temperature-sensitive coil spring 5 have a large spring load. Consequently, if a temperature-sensitive coil spring with a large generated load is used, there arises a problem that the size of the hot water-water mixing faucet A to be assembled increases.
Furthermore, when the temperature-regulating dial D1 is turned to move the control valve body 3, and the space between the cold-water valve seat b and the cold-water valve 3b is completely closed while the space between the hot-water valve seat a and the hot-water valve 3a is opened in order to eject the hot water, or when the space between the hot-water valve seat a and the hot-water valve 3a is completely closed while the space between the cold-water valve seat b and the cold-water valve 3b is opened in order to eject the cold water, there arises a problem that the flow of the cold water or the hot water is shut off suddenly, causing a hunting phenomenon, damaging the apparatus.
Moreover, in the hot water-water mixing faucet A in which the control valve body 3 is connected with the temperature-sensitive coil spring 5 and the bias spring 4 such that the temperature-sensitive coil spring 5 and the bias spring 4 are allowed to face each other, whereby the control valve body 3 is supported by the balance between these two springs so as to be able to move in the axial direction, since the balance between the two opposing springs causes the control valve body 3 to perform a control operation, the operation of the control valve body 3 becomes uncoordinated if the area of contact in each of the connected positions between the control valve body 3 and the two springs is changed. Therefore, in order to facilitate the operation smoothly, it is required to flatten the end surface, which is the point of connection between the control valve body 3 and each of the two springs, so that the spring pressure correctly acts on the control valve body 3 even if bending occurs on the springs, thus there arises a problem that the cost of manufacturing the springs increases.
A problem to be solved by the present invention is, first of all, a development of the means of completely closing the space between the hot-water valve 3a and the hot-water valve seat a when ejecting the cold water, without increasing the size of the temperature-sensitive coil spring 5 constituted by the SMA spring. The second problem is a development of the means of effectively avoiding the hunting phenomenon which occurs when the space between the cold-water valve seat b and the cold-water valve 3b or the space between the hot-water valve seat a and the hot-water valve 3a is closed suddenly. The third problem is a development of the means of using the two springs, i.e. the temperature-sensitive coil spring 5 and the bias spring 4, in a manner that they face each other, so that, without performing processing of polishing the end surfaces of the springs to obtain flat surfaces, the control valve body 3 smoothly operates when the balance between the springs causes the control valve body 3 to carry out its control operation.